From: Christian Brauner <christian@brauner.io>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-kernel@vger.kernel.org, arnd@arndb.de,
ebiederm@xmission.com, keescook@chromium.org,
joel@joelfernandes.org, tglx@linutronix.de, tj@kernel.org,
dhowells@redhat.com, jannh@google.com, luto@kernel.org,
akpm@linux-foundation.org, cyphar@cyphar.com,
torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
kernel-team@android.com, linux-api@vger.kernel.org
Subject: Re: [PATCH 2/5] pidfd: add pidfd_wait()
Date: Thu, 25 Jul 2019 12:21:56 +0200 [thread overview]
Message-ID: <20190725102156.nqnngsrb6dwmyztb@brauner.io> (raw)
In-Reply-To: <20190725101626.GD4707@redhat.com>
On Thu, Jul 25, 2019 at 12:16:27PM +0200, Oleg Nesterov wrote:
> On 07/24, Christian Brauner wrote:
> >
> > +SYSCALL_DEFINE6(pidfd_wait, int, pidfd, int __user *, stat_addr,
> > + siginfo_t __user *, info, struct rusage __user *, ru,
> > + unsigned int, states, unsigned int, flags)
> > +{
>
> Oh, I too think that P_PIDFD makes more sense.
I have already updated the patch to introduce P_PIDFD.
>
> and could you explain in the changelog why? I am not arguing and if
> nothing else this is consistent with other pidfd features, but if you
> are parent/debugger you can't hit the problem with pid-reuse, unless
> you races with your sub-threads.
One of the things is that later on this will allow us to make it
possible to retrieve the exit status via waitid(P_PIDFD) for non-parent
processes if handed a _suitable_ pidfd that has this feature set. Maybe
even - if safe - make it possible to wait on a process as a non-parent.
And some tools just really want to do away with pids completely.
Christian
next prev parent reply other threads:[~2019-07-25 10:22 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-24 14:46 [PATCH 0/5] pidfd: waiting on processes through pidfds Christian Brauner
2019-07-24 14:46 ` [RFC][PATCH 1/5] exit: kill struct waitid_info Christian Brauner
2019-07-24 17:37 ` Linus Torvalds
2019-07-24 22:01 ` Christian Brauner
2019-07-25 12:46 ` Eric W. Biederman
2019-07-26 8:01 ` Christian Brauner
2019-07-26 11:59 ` Eric W. Biederman
2019-07-26 12:37 ` Christian Brauner
2019-07-25 9:40 ` Oleg Nesterov
2019-07-25 10:07 ` Christian Brauner
2019-07-24 14:46 ` [PATCH 2/5] pidfd: add pidfd_wait() Christian Brauner
2019-07-24 17:45 ` Linus Torvalds
2019-07-24 17:50 ` Christian Brauner
2019-07-24 17:52 ` Christian Brauner
2019-07-25 14:34 ` Eric W. Biederman
2019-07-25 10:16 ` Oleg Nesterov
2019-07-25 10:21 ` Christian Brauner [this message]
2019-07-26 8:19 ` Arnd Bergmann
2019-07-26 8:24 ` Christian Brauner
2019-07-26 9:57 ` Arnd Bergmann
2019-07-24 14:46 ` [PATCH 3/5] arch: wire-up pidfd_wait() Christian Brauner
2019-07-24 14:46 ` [PATCH 4/5] pidfd: add CLONE_WAIT_PID Christian Brauner
2019-07-24 18:14 ` Jann Horn
2019-07-24 18:27 ` Christian Brauner
2019-07-24 19:07 ` Jann Horn
2019-07-24 19:10 ` Christian Brauner
2019-07-25 10:11 ` Christian Brauner
2019-07-25 10:30 ` Oleg Nesterov
2019-07-25 10:36 ` Christian Brauner
2019-07-25 10:35 ` Oleg Nesterov
2019-07-25 10:40 ` Christian Brauner
2019-07-25 11:25 ` Oleg Nesterov
2019-07-25 11:41 ` Christian Brauner
2019-07-25 11:43 ` Oleg Nesterov
2019-07-25 12:26 ` Christian Brauner
2019-07-25 16:13 ` Oleg Nesterov
2019-07-25 16:56 ` Christian Brauner
2019-07-25 16:57 ` Eric W. Biederman
2019-07-24 14:46 ` [PATCH 5/5] pidfd: add pidfd_wait tests Christian Brauner
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